Fine Cyclo W-Series

High precision gearbox with extremely large hollow shaft & built-in pre-stage

High load precision gearbox with huge hollow bore and integrated pre-stage.

  • Less than 1 arcmin Lost Motion
  • Ideal for robot base axes
  • Input and output on same side
  • Hollow shaft rotates with output speed
  • Additional ratios possible on request (different pre-stage)
  • Motor coupling and adapter on request
Zero Mechanical Backlash
Lost Motion <1 arcmin
Number of Sizes 2
Reduction Ratios depending on pre-stage
Nominal Torque 2453 Nm / 4000 Nm
Acceleration Torque 6130 Nm / 10000 Nm
Max. Momentary Peak Torque 9810 Nm / 20000 nm
Output Speed 30 rpm / 25 rpm
Max. Bending Moment 9565 Nm / 22000 Nm
Bending Stiffness up to 15700 Nm/arcmin
Max. Axial Load 13734 N / 29400 N
Torsional stiffness up to 1960 Nm/arcmin

Key Product Facts

10000 Nm
Acceleration Torque
138 mm
Hollow Shaft Bore
1960 Nm/arcmin
Torsional stiffness

Advantages of Fine Cyclo W-Series

Very smooth traverse movements

High Torsional Stiffness

Small Moments Of Inertia

High Efficiency

Easy Assembly And Motor Mounting

Lifetime Lubricated For Any Position

Main dimensions and mass

Dimensions W-Series


Size Length L [mm] Diameter G [mm] Diameter D [mm] Diameter H [mm] Mass [kg]
W55 129.5 355 258 90 68
W70 175.5 470 390 138 95

Design of input stage on customer request

Torque and Speed main data

Size Nominal output torque
(1) [Nm]
Max Accel. / decel. torque [Nm] Max output speed [rpm]
W55 2453 6130 30
W70 4000 10000 25

(1) at output speed n2=15 rpm

Output bearing capacity

Size Max permissible bending moment [Nm] Max permissible axial load [N]
W55 9565 13734
W70 22000 29400

Available ratios

Size Ratios
W55 64
W70 87.3

Additional ratios depending on prestage

Above technical specifications are intended for rough preselection only.

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Please contact us for specific motor adaption and other customization:

We offer almost any desired option, from a motor adapter to an assembly that includes the motor and is ready for mounting right out of the box. Contact your Sumitomo representative for more details.

The Servo 100, Servo 6000, and Fine Cyclo reducers can withstand momentary shock loads as high as 500% of the rated torque.

Customers should never open the Fine Cyclo. The reduction stages of the FA-Series reducers are lubricated for life. Additionally, their internal components are matched in such a way that makes re-assembly very difficult for untrained personnel. If desired, customers may return Fine Cyclos to Sumitomo for grease replenishment after 5 years in order to increase service life.

Emergency After-Hours Support


Sumitomo’s Product Support offers scheduled repair services as a one-stop-shop for all your related gearbox needs. For emergency repairs, we offer repair services 24 hours a day, 7 days a week.

Cyclo and Spur Gear

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